Lead insertion devices and associated systems and methods

ABSTRACT

Insertion devices and associated systems and methods for the percutaneous placement of patient leads are disclosed herein. A system in accordance with a particular embodiment includes a cannula having a lumen and a first dilator. The first dilator can be positioned within the lumen and the first dilator and the cannula can be used to create a percutaneous entry point. An additional dilator can be positioned over the first dilator and advanced into the percutaneous entry point to expand the percutaneous entry point. A final dilator can be inserted into the patient and two leads can be advanced into the patient through the final dilator.

The present application is a divisional of U.S. patent application Ser.No. 15/085,913, filed Mar. 30, 2016, which is a divisional of U.S.patent application Ser. No. 13/710,341, filed on Dec. 10, 2012, whichare incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present technology is directed generally to insertion devices forpercutaneously placing patient leads, and associated systems andmethods. Insertion devices, and associated systems and methods inaccordance with the present technology are suitable for placing multipleleads through a single percutaneous access point.

BACKGROUND

Neurological stimulators have been developed to treat pain, movementdisorders, functional disorders, spasticity, cancer, cardiac disorders,and various other medical conditions. Implantable neurologicalstimulation systems generally have an implantable pulse generator (IPG)that is operably coupled to one or more leads that deliver electricalpulses to neurological tissue or muscle tissue. For example, severalneurological stimulation systems for spinal cord stimulation (SCS) havecylindrical leads that include a lead body with a circularcross-sectional shape and multiple conductive rings spaced apart fromeach other at the distal end of the lead body. The conductive ringsoperate as individual electrodes or contacts to deliver electricalsignals to the patient. The SCS leads are typically implanted eithersurgically or percutaneously through a needle inserted into the epiduralspace, often with the assistance of a stylet.

Once implanted, the pulse generator applies electrical pulses to theelectrodes, which in turn modify the function of the patient's nervoussystem, such as by altering the patients responsiveness to sensorystimuli and/or altering the patient's motor-circuit output. Inparticular, the electrical pulses can generate sensations that mask orotherwise alter the patient's sensation of pain. For example, in manycases, patients report a tingling or paresthesia that is perceived asmore pleasant and/or less uncomfortable than the underlying painsensation. In other cases, the patients can report pain relief withoutparesthesia or other sensations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially schematic illustration of a spinal cordstimulation system positioned to deliver therapeutic signals inaccordance with an embodiment of the present technology.

FIGS. 2-4 are isometric views of an insertion needle having a cannulaand a stylet configured in accordance with an embodiment of the presenttechnology.

FIGS. 5A and 5B are isometric and cross-sectional side views,respectively, of a dilator configured in accordance with anotherembodiment of the present technology.

FIGS. 6A and 6B are isometric views of a dilator and a cannula during aprocedure in accordance with an embodiment of the present technology.

FIGS. 7A and 7B are isometric views of a set of dilators configured inaccordance with a further embodiment of the present technology.

FIG. 8 is an isometric view of a first dilator and a second dilatorduring a procedure in accordance with an embodiment of the presenttechnology.

FIG. 9 is an isometric view of a dilator configured in accordance withanother embodiment of the present technology.

FIG. 10 is an isometric view of a set of dilators configured inaccordance with a further embodiment of the present technology.

FIG. 11 is a partially schematic isometric view of a dilator having amapping contact configured in accordance with another embodiment of thepresent technology.

DETAILED DESCRIPTION

The present technology is directed generally to insertion devices andsystems and methods for neuromodulation systems, and more specificallyto single access or single entrance point insertion systems forimplanting spinal cord modulation leads. Several embodiments of thepresent technology include access systems having insertion needles andmultiple dilators. In various embodiments, the insertion needles anddilators are configured in a variety of suitable manners and can beemployed independently or together to implant multiple leads through asingle percutaneous entry point in a patient. For example, the presenttechnology can include an insertion needle having a cannula, a stylet,and a series of dilators that can operate together to open and expand asingle percutaneous entry point in a patient. In other embodiments, thedevices, systems and associated methods can have differentconfigurations, components, and/or procedures. Still other embodimentsmay eliminate particular components and/or procedures. Additionally, thepresent technology, which includes associated devices, systems,procedures, methods of use, and instructions for steps included in amethod of use, may include other embodiments with additional elements orsteps, and/or may include other embodiments with or without several ofthe features or steps shown and described below with reference to FIGS.1-11. Further, while embodiments presented in FIG. 1 may describe leadimplantation in spinal cord stimulation systems, other embodiments ofthe presented technology are applicable in other fields and/or otherneuromodulation settings and/or other surgical lead or toolimplantations.

FIG. 1 schematically illustrates a representative patient system 100 forproviding relief from chronic pain and/or other conditions, arrangedrelative to the general anatomy of a patient's spinal cord 191. Theoverall patient system 100 can include one or more signal deliverydevices 110, which may be implanted within a patient 190, typically ator near the patient's spinal cord midline 189, coupled to an implantablepulse generator 101. The signal delivery devices 110 carry features fordelivering therapy to the patient 190 after implantation. The pulsegenerator 101 can be connected directly to the signal delivery devices110, or it can be coupled to the signal delivery devices 110 via asignal link or lead extension 102. In a further representativeembodiment, the signal delivery devices 110 can include one or moreelongated lead(s) or lead body or bodies 111 (identified individually asa first lead 111 a and a second lead 111 b). As used herein, the terms“lead” and “lead body” include any of a number of suitable substratesand/or support members that carry devices for providing therapy signalsto the patient 190. For example, the lead or leads 111 can include oneor more electrodes or electrical contacts that direct electrical signalsinto the patient's tissue, such as to provide for patient pain relief.In other embodiments, the signal delivery devices 110 can includestructures other than a lead body (e.g., a paddle) that also directelectrical signals and/or other types of signals to the patient 190.

The pulse generator 101 can transmit therapy signals (e.g., electricalsignals) to the signal delivery devices 110 that up-regulate (e.g.,stimulate or excite) and/or down-regulate (e.g., block or suppress)target nerves. As used herein, and unless otherwise noted, to “modulate”or provide “modulation” to the target nerves refers generally to havingeither type of the foregoing effects on the target nerves. The pulsegenerator 101 can include a machine-readable (e.g., computer-readable)medium containing instructions for generating and transmitting suitabletherapy signals. The pulse generator 101 and/or other elements of thesystem 100 can include one or more processor(s) 107, memory unit(s) 108and/or input/output device(s) 112. Accordingly, the process of providingelectrical signals, providing guidance information for positioning thesignal delivery devices 110, and/or executing other associated functionscan be performed by computer-executable instructions contained bycomputer-readable media located at the pulse generator 101 and/or othersystem components. The pulse generator 101 can include multipleportions, elements, and/or subsystems (e.g., for directing signals inaccordance with multiple signal delivery parameters), carried in asingle housing, as shown in FIG. 1, or in multiple housings.

In some embodiments, the pulse generator 101 can obtain power togenerate the therapy signals from an external power source 103. Theexternal power source 103 can transmit power to the implanted pulsegenerator 101 using electromagnetic induction (e.g., RF signals). Forexample, the external power source 103 can include an external coil 104that communicates with a corresponding internal coil (not shown) withinthe implantable pulse generator 101. The external power source 103 canbe portable for ease of use.

During at least some procedures, an external stimulator or trialmodulator 105 can be coupled to the signal delivery devices 110 duringan initial procedure, prior to implanting the pulse generator 101. Forexample, a practitioner (e.g., a physician and/or a companyrepresentative) can use the trial modulator 105 to vary therapyparameters provided to the signal delivery devices 110 in real time, andselect optimal or particularly efficacious parameters. These parameterscan include the location from which the electrical signals are emitted,as well as the characteristics of the electrical signals provided to thesignal delivery devices 110. In a typical process, the practitioner usesa cable assembly 120 to temporarily connect the trial modulator 105 tothe signal delivery devices 110. The practitioner can test the efficacyof the signal delivery devices 110 in an initial position. Thepractitioner can then disconnect the cable assembly 120 (e.g., at aconnector 122), reposition the signal delivery devices 110, and reapplythe electrical signals. This process can be performed iteratively untilthe practitioner obtains the desired position for the signal deliverydevices 110. Optionally, the practitioner may move the partiallyimplanted signal delivery devices 110 without disconnecting the cableassembly 120. Furthermore, in some embodiments, the iterative process ofrepositioning the signal delivery devices 110 and/or varying the therapyparameters, may not be performed.

The pulse generator 101, the lead extension 102, the trial modulator 105and/or the connector 122 can each include a receiving element 109.Accordingly, the receiving elements 109 can be patient implantableelements, or the receiving elements 109 can be integral with an externalpatient treatment element, device or component (e.g., the trialmodulator 105 and/or the connector 122). The receiving elements 109 canbe configured to facilitate a simple coupling and decoupling procedurebetween the signal delivery devices 110, the lead extension 102, thepulse generator 101, the trial modulator 105 and/or the connector 122.Receiving elements 109 can be at least generally similar in structureand function to those described in U.S. patent application Ser. No.13/291,985, entitled MEDICAL DEVICE CONTACT ASSEMBLIES FOR USE WITHIMPLANTABLE LEADS, AND ASSOCIATED SYSTEMS AND METHODS, filed Nov. 8,2011, which is incorporated by reference herein in its entirety. To theextent any of the foregoing patents, patent applications and/or anyother materials incorporated herein by reference conflict with thepresent disclosure, the present disclosure controls.

After a trial period with the trial modulator 105, the practitioner canimplant the implantable pulse generator 101 within the patient 190 forlonger term treatment. The signal delivery parameters provided by thepulse generator 101 can still be updated after the pulse generator 101is implanted, via a wireless physician's programmer 117 (e.g., aphysician's laptop, physician's remote, etc.) and/or a wireless patientprogrammer 106 (e.g., a patient's laptop, patient's remote, etc.).

Inserting SCS leads percutaneously can provide a less invasive procedurethan direct surgical implantation of the leads. Percutaneous insertioncan reduce patient discomfort and recovery time associated with theprocedure. In many instances, it is preferable to insert more than oneSCS lead at a given treatment location. For example, two cylindricalleads are often positioned proximate to each other at a treatmentlocation. Current percutaneous insertion devices require separateaccess/entrance points for inserting each individual lead into theepidural space, or other suitable implant location. However, eachadditional access/entrance point increases patient discomfort andincreases the probability of infection. Accordingly, presented herein isa percutaneous implantation system that facilitates implanting multipleSCS leads through a single access/entrance point.

FIGS. 2-4 are isometric views of an insertion needle 200 having acannula 202 and a stylet 204 configured to implant leads, such as signaldelivery devices 111 a and/or 111 b of FIG. 1, in accordance with anembodiment of the present technology. FIG. 2 illustrates the insertionneedle 200 in a disassembled state, with the cannula 202 and the stylet204 spaced apart from each other. FIGS. 3 and 4 illustrate the insertionneedle 200 in an assembled state, with the stylet 204 positioned within,and removeably coupled to, the cannula 202, as described further below.Referring first to FIG. 2, the cannula 202 includes a lumen 203 thatextends from a proximal end 206 to a distal end 208. The proximal end206 can include a cannula hub 205 and the distal end 208 can have abeveled cannula tip 207.

Similarly, the stylet 204 extends from a proximal end 210 having astylet hub 209 to a distal end 212 having a beveled stylet tip 211. Thestylet 204 in the illustrated embodiment includes a solid cylinder 213that extends from the stylet hub 209 to the beveled stylet tip 211.However, in some embodiments, the stylet 204 can include a lumen and/orother non-solid portions. In one embodiment, the stylet 204 includes aremovable hub 209. As further described below, inclusion of a removablehub 209 allows the stylet 204 to serve both its primary function ofaiding in the insertion of the cannula 202, as well as a secondaryfunction of acting as a first dilator or dilator guide.

The cannula 202 in the illustrated embodiments of FIGS. 2-4 is a 14gauge cannula. In some embodiments, the cannula 202 can be of a size inthe range of 12 gauge to 18 gauge. In other embodiments, the cannula 202can be larger than 12 gauge, or smaller than 18 gauge. The lumen 203 ofthe cannula 202 can be configured to receive the stylet 204 forassembling the insertion needle 200. For example, the distal end 212 ofthe stylet 204 can be inserted into the cannula lumen 203 at theproximal end 206 of the cannula 202. The stylet 204 can be advancedwithin the lumen 203 until the stylet hub 209 contacts and/or engagesthe cannula hub 205, as shown in FIG. 3. The beveled stylet tip 211 canbe shaped to match the beveled cannula tip 207. For example, when thestylet 204 is fully inserted into the cannula 202, the beveled cannulatip 207 and the beveled stylet tip 211 can align to form a generallyuniform beveled insertion needle tip 402, as shown in FIG. 4.Additionally, in some embodiments, the cannula hub 205 (FIG. 2) canreleasably engage with the stylet hub 209 to removeably couple thestylet 204 to the cannula 202. In one embodiment, the cannula hub 205mates with the stylet hub 209 in only one position so as to align thestylet tip 211 with the cannula tip 207, thereby establishing theuniform beveled insertion needle tip 402.

The beveled insertion needle tip 402 can be shaped in a variety ofsuitable manners. For example, in the illustrated embodiment, thebeveled insertion needle tip 402 is generally “shovel” shaped (e.g.,curved). In other embodiments, the beveled insertion needle tip 402 caninclude a beveled end that is straight, rather than curved. In stillother embodiments, the insertion needle tip 402 can include othersuitable shapes or configurations, e.g., compound curves. Further, thestylet tip 211 and the cannula tip 207 may be configured such that theircombined surface area reduces the amount of directed pressure thebeveled insertion needle tip 402 exerts on a tissue-needle interface(i.e., the pressure on the patient tissue at the point of insertion ofthe needle 200).

In operation, an assembled insertion needle 200 can be inserted into apatient to create a percutaneous entry point. During insertion, thesolid stylet 204 can “block” the cannula lumen 203 and reduce thepossibility of “needle hole” injuries and/or other potentialcomplications. For example, the beveled insertion needle tip 402 withthe solid stylet 204 can act as a sharp wedge that opens up apercutaneous entry point in a patient without “coring” a hole in thepatient. I.e., the solid stylet 204 can effectively close off theentrance to the lumen 203 at the distal end 208 of the cannula 202,thereby reducing the possibility for the cannula 202 to cut a “core” ofskin from the patient. After the percutaneous entry point has beencreated, the stylet 204 can be removed from the cannula 202. Forexample, the stylet 204 can be extracted from the cannula 202 bygrasping and pulling the stylet hub 209 while holding the cannula hub205 (FIGS. 2 and 3). Removing the stylet 204 can provide for expanding apercutaneous entry point, as described below. Alternatively, the stylethub 209 may be removed, and the cannula 202 may be withdrawn over thestylet 204. With the stylet hub 209 removed, the stylet 204 may serve asan initial dilator or dilator guide for further opening of thepercutaneous entry point.

FIGS. 5A and 5B are isometric and cross-sectional side views,respectively, of a dilator 502 configured in accordance with anembodiment of the present technology. The dilator 502 can be used inconjunction with the cannula 202 and the stylet 204 shown in FIGS. 2-4,as will be described further below. In the illustrated embodiment, thedilator 502 includes a lumen 504 extending through the dilator 502 froma proximal end 506 to a distal end 508. The distal end 508 of thedilator 502 can include a tapered section 510, and the outside diameterof the dilator 502 can vary from a first diameter D1 at the distal end508 to a second diameter D2, greater than the first diameter D1, at theproximal end 506. The dilator 502 can be configured to be receivedwithin the cannula 202. For example, the second diameter D2 can be lessthan the width of the cannula lumen 203 (FIG. 2), such that the dilator502 can be inserted into the lumen 203. The dilator 502 may also beconfigured to be received over the stylet 213. For example, the firstand second diameter D1 and D2 can be greater than the outer diameter ofthe stylet 213. The dilator 502 can be constructed from a variety ofsuitable materials (e.g., polypropylene, polytetrafluoroethylene (PTFE),Delrin, high density polyethylene (HDPE), low density polyethylene(LDPE), or Teflon) and can be constructed to have varying amounts offlexibility. For example, in some embodiments the dilator 502 can beflexible and soft (e.g., bendable along a longitudinal axis andrelatively pliable), and in other embodiments the dilator 502 can berigid and stiff (e.g., unbendable about a longitudinal axis andrelatively unpliable). Additionally, the dilator 502 can be constructedwith materials that are loaded with barium, e.g., polypropylene loadedwith barium or Teflon loaded with barium. In embodiments having barium,the dilator 502 can be radiopaque, which can be beneficial forradiographic imaging techniques.

FIGS. 6A and 6B are isometric views of the dilator 502 and the cannula202 during a procedure in accordance with an embodiment of the presenttechnology. As shown in FIG. 6A, the practitioner inserts the cannula202 through a percutaneous entry point 602 into a patient 190, toposition a distal end (not visible) of the cannula 202 beneath thepatient's skin. The dilator 502 in FIG. 6A is positioned for insertioninto the patient 190 through the cannula lumen 203. For example, afterremoval of the stylet 204 (FIGS. 2-4), the distal end 508 of the dilator502 can be inserted into the lumen 203, and the distal end 508 can beadvanced in the direction of arrow A₁ past the percutaneous entry point602. Accordingly, the dilator 502 can extend through the percutaneousentry point 602 within the lumen 203. It should be noted that thedilator 502 is of a length that is greater than the length of thecannula 202. After the dilator 502 has been positioned to extend throughthe percutaneous entry point 602, the cannula 202 can be removed, asillustrated in FIG. 6B. In the illustrated embodiment of FIG. 6B, thedilator 502 extends through the percutaneous entry point 602. Thecannula 202 can be removed by grasping and pulling the cannula hub 205in the direction of arrow A₂ until the cannula 202 is separated from thedilator 502. In the illustrated embodiment, the dilator 502 has anoverall length that is longer than the length of the cannula 202. Insuch embodiments, the proximal end 506 of the dilator 502 can be heldwhile the cannula 202 is pulled in the direction of A₂ to remove thecannula 202 from the patient 190. As the cannula 202 is moved in thedirection of A₂, past the percutaneous entry point 602, a portion 604 ofthe dilator 502 is exposed near the percutaneous entry point 602. Thepractitioner can hold this portion 604 of the dilator 502 in place ashe/she moves the cannula 202 further in the direction of A₂ andseparates the cannula 202 from the dilator 502.

FIGS. 7A and 7B are isometric views of a set of dilators 702 (identifiedindividually as first-sixth dilators 702 a-702 f) configured inaccordance with an embodiment of the present technology. FIG. 7Aillustrates the entire length of each of the dilators 702, while FIG. 7Bis a close-up view illustrating a distal end of each of the dilators702. Referring to FIGS. 7A and 7B, together, each of the dilators 702can be at least generally similar in structure and function to thedilator 502 shown in FIGS. 5A-6B. In the illustrated embodiments, thedilators 702 have corresponding increasing outside diameters OD(identified individually as first-sixth outside diameters OD1-OD6).Additionally, the dilators 702 include corresponding lumens 703 havingincreasing inside diameters ID (identified individually as first-sixthinside diameters ID1-ID6). In a particular embodiment, the sixth dilator702 f is the last or final dilator, while in other embodiments, thedilator set 702 can include any suitable number of dilators greater thanor equal to two. The second dilator 702 b through the sixth dilator 702f can be configured to fit over the corresponding next smallest dilator702 (e.g., the first dilator 702 a through the fifth dilator 702 e). Forexample, the second dilator 702 b includes an inside diameter ID2 thatis larger than the outside diameter OD1 of the first dilator 702 a, suchthat the second dilator 702 b can slide over the first dilator 702 a.

FIG. 8 is an isometric view of the first dilator 702 a and the seconddilator 702 b during a procedure in accordance with an embodiment of thepresent technology. As discussed above, the second or other subsequentdilator 702 b can be configured to fit over the first or other precedingdilator 702 a. In the illustrated embodiment, the first dilator 702 a ispositioned to extend through the percutaneous entry point 602 into thepatient 190. The first dilator 702 a can be inserted into the patient190 in a manner at least generally similar to that described above withrespect to the dilator 502 shown in FIGS. 5A-6B. The second dilator 702b can be positioned over the first dilator 702 a and maneuvered toexpand the percutaneous entry point 602. For example, the second dilator702 b can be advanced in the direction of arrow A₁ along the firstdilator 702 a. A tapered portion 810 of the second dilator 702 b can actto expand the percutaneous entry point 602 as the second dilator 702 bis moved further in the direction of arrow A₁. As the second dilator 702b is moved further in the direction of arrow A₁, a proximal end (notshown) of the first dilator 702 a can extend out of a distal end 812 ofthe second dilator 702 b. The practitioner can grasp the proximal end ofthe first dilator 702 a and remove it from the patient 190 and fromwithin the second dilator 702 b. This process can be halted after twodilators, or repeated with any suitable number of additional dilators,e.g., the third dilator 702 c through the final dilator 702 f, toincrementally expand the percutaneous entry point 602. The expansion ofthe percutaneous entry point 602 obtained by increasing the outsidediameters ODs of successive dilators 702 corresponds to an increase inthe inside diameters IDs of the lumens 703 of the dilators 702. This canproduce a desired final inside diameter ID large enough to accommodateinserted signal delivery devices (e.g., leads).

In one embodiment, the final dilator 702 can be selected to have aninside diameter ID that simultaneously accommodates two leads, e.g.,side by side. For example, a particular lead can have an approximateexternal diameter of 4 French (1.33 mm). Accordingly, a dilator 702having an inside diameter ID slightly larger than 8 French (2.66 mm),e.g., a dilator having a 9 French (3 mm) inside diameter ID, can be thefinal dilator 702 that is inserted through a percutaneous entry point,thereby allowing two 4 French leads to be inserted through the dilatorlumen 703 in a side by side configuration. In other embodiments,dilators 702 having lumens 703 with different sized inside diameters IDcan be chosen to accommodate the insertion of two or more devices havinglarger or smaller dimensions than the 4 French leads discussed above. Insome embodiments, dilators 702 can include lumens 703 having insidediameters IDs chosen to accommodate two leads having different externaldiameters. For example, in one embodiment, a dilator 702 having an 8French inside diameter ID can accommodate a first lead having a 3 Frenchexternal diameter and a second lead having a 4 French external diameter.Additionally, although the external diameter of the leads discussedherein can include a diameter of a circular cross-section, the termexternal diameter, and/or diameter, can include a variety of otherdimensions.

Although the illustrated embodiment of FIG. 7 includes six dilators 702,other embodiments can include additional or fewer dilators 702. Forexample, in some embodiments, two dilators 702 can be sufficient toexpand a percutaneous entry point to the desired inside diameter ID.Accordingly, in some embodiments only the first dilator 702 a and thesecond dilator 702 b may be used. In other embodiments, a cannula havinga lumen sized to receive the third dilator 702 c may be used, and thethird dilator 702 c may be used with the fourth dilator 702 d to expandthe percutaneous entry point. In some embodiments, a set of dilators maybe provided together as a group, and the appropriate dilators 702 may beselected for a particular procedure. Additionally, in the illustratedembodiment of FIG. 7, the length of each dilator 702 is at leastapproximately equal. In other embodiments, the length of each dilator702 can decrease as the diameter increases. In this manner, when asubsequent dilator 702 is positioned over a preceding dilator 702 andadvanced to the same depth within a patient, a proximal end of thepreceding dilator 702 remains exposed. Accordingly, a physician,surgeon, or other medical practitioner can grasp the proximal end of thepreceding dilator 702 to remove it from within the patient 190, withoutneeding to insert the subsequent dilator 702 deeper than the precedingdilator 702.

FIG. 9 is an isometric view of a dilator 902 configured in accordancewith a further embodiment of the present technology. The dilator 902 canbe at least generally similar in structure and function to the dilators502 and 702 described above with respect to FIGS. 5A to 8. For example,the dilator 902 can be constructed from a variety of suitable materials,including, e.g., polypropylene, PTFE, and Teflon. However, in theillustrated embodiment, the dilator 902 includes a solid tube 904extending from a proximal end 906 to a distal end 908. Additionally, thedistal end 908 includes a shovel-shaped beveled dilator tip 910. Thebeveled dilator tip 910 can be shaped to match the beveled stylet tip211 (FIG. 4). In one embodiment, the dilator 902 can be used in place ofthe stylet 204 to create a percutaneous entry point. For example, thedilator 902 can be positioned within the cannula 202 (FIGS. 2-4) withthe beveled dilator tip 910 aligning with the beveled cannula tip 207.In operation, the practitioner can simultaneously insert the cannula 202and the dilator 902 into a patient to create the percutaneous entrypoint, with the solid core of the dilator 902 blocking the cannula lumen203, e.g., to prevent tissue coring. Accordingly, the dilator 902 canreduce the possibility for injuries in a manner at least generallysimilar to those described above with respect to the stylet 204. In someembodiments, the dilator 902 can include an aperture or lumen, or othernon-solid portion (e.g., a blind hole), small enough to not causecoring.

The dilator 902 can also reduce the number of steps required to positiona dilator 702 having a desired inside diameter ID. For example, incontrast to the procedure described above with respect to FIGS. 2-6B,after the percutaneous entry point has been created with the cannula 202and the dilator 902, the cannula 202 can be removed from the patient,leaving the dilator 902 extending through the percutaneous entry point.One of the dilators 702 can subsequently be positioned over the dilator902 and advanced into the patient. Accordingly, the dilator 902 canobviate the need to replace the stylet 204 with a first dilator 702 aprior to inserting a second dilator 702 b.

The dilator 902 in FIG. 9 includes a proximal end 906 having no hub.However, in some embodiments, a removable hub can be added to thedilator 902 at the proximal end 906 to facilitate creating apercutaneous entry point. The removable hub can operably couple thedilator 902 to the cannula 202 and/or can aid in maintaining thealignment of the beveled dilator tip 910 with the beveled cannula tip207. The removable hub can be separated from the dilator 902 after thepercutaneous entry point has been created, thereby allowing the cannula202 to be removed over the dilator 902. In other embodiments, otherdevices, structures or methods can be used to maintain the alignment ofthe cannula 202 and the dilator 902 relative to each other as thepractitioner creates the percutaneous entry point. For example, thecannula hub 205 can include a mechanism that can removeably couple thedilator 902 to the cannula 202. In one embodiment, this can include atube clamp (e.g., a tube clamp having a quick release mechanism). Inother embodiments, other securing mechanisms can be used to temporarilysecure the dilator 902 within the cannula 202 (e.g., male and femalethreads). Furthermore, in some embodiments, the dilator 902 can includea compressible hub at the proximal end 906. The compressible hub canassist in maintaining the position of the dilator 902 within the cannula202 and/or aligning the beveled dilator tip 910 and the beveled cannulatip 207, and can also be compressed to fit through the cannula lumen203. Although various embodiments described herein include descriptionsof methods of use, other embodiments can include instructing one or moresteps included in a method of use.

FIG. 10 is an isometric view of a set of dilators 1002 (identifiedindividually as a first-fourth (e.g., final) dilator 1002 a-1002 d)configured in accordance with an embodiment of the present technology.Similar to the dilators 702 described above, the dilators 1002 can beused to expand a percutaneous entry point to provide for the insertionof other medical devices. For example, the dilators 1002 include lumens1003 that increase in size from the first dilator 1002 a to the finaldilator 1002 d. However, the cross-sectional shape of the dilators 1002and the lumens 1003 in the second dilator 1002 b through the finaldilator 1002 d is not circular, but elliptical. In particular, thesecond-fourth dilators 1002 b-1002 d, and their respective lumens 1003,have widths along a first cross-sectional axis W_(F) that are longerthan the widths along a second cross-sectional axis W_(S). Theelliptical shape of the second-final dilator 1002 b-1002 d can allow oneor more medical devices to be inserted through a smaller percutaneousentry point. In one embodiment, the lumen 1003 of the final dilator 1002d can be sized to allow two cylindrical leads to pass throughsimultaneously. For example, in a particular embodiment, the width ofthe dilator lumen 1003 along the first cross-sectional axis W_(F) forthe final dilator 1002 d can be approximately 9 French (3 mm) toaccommodate two 4 French (1.33 mm) leads side by side along the firstcross-sectional axis W_(F). With the leads positioned side by side alongthe first cross-sectional axis W_(F), the dilator 1002 d can have asmaller width along the second cross-sectional axis W_(S). For example,in one embodiment, the lumen 1003 can have a width along the secondcross-sectional axis W_(S) of approximately 5 French (1.66 mm).Accordingly, the dilator 1002 d can have a smaller outside dimension,and thereby produce a smaller percutaneous entry than that produced by adilator having a round cross-sectional area. Although the example abovedescribes dimensions designed to accommodate two 4 French (1.33 mm)leads, in other embodiments, the size of the lumens 1003 can be smalleror larger than this example to provide a desired size for the insertionof two or more medical devices having larger or smaller dimensions.Additionally, although the illustrated embodiment includes four dilators1002, other embodiments may include more or fewer dilators 1002.

The dilators 1002 can be employed in a manner at least generally similarto the dilators 702 and 902 described above. For example, after apercutaneous entry point has been created with the cannula 202 and thestylet 204, the stylet 204 can be removed, the first dilator 1002 a canbe inserted into the cannula 204, the cannula 204 can be removed fromthe patient, and the second dilator 1002 b through the final dilator1002 d can be sequentially inserted into the patient over the precedingdilator to expand the percutaneous entry point. Alternatively, thedilator 902 can be used in conjunction with the cannula 202 (asdescribed above) and the second dilator 1002 b through the final dilator1002 d can be sequentially inserted into the patient over the precedingdilator to expand the percutaneous entry point.

FIG. 11 is a partially schematic isometric view of a dilator 1102 havinga mapping contact 1104 configured in accordance with another embodimentof the present technology. The dilator 1102 can be at least generallysimilar in structure and function to the dilator 1002 described abovewith respect to FIG. 10. However, the dilator 1102 can be used incombination with the cannula 202 to both create a percutaneous entrypoint and to identify penetration of a patient's dura. In theillustrated embodiment, the mapping contact 1104 includes a metallicband 1105 that extends around the circumference of the dilator 1102 at adistal end 1112 of the dilator 1102. A pair of conducting lines 1106 canconnect the contact 1104 to a plug 1108 at a proximal end 1110 of thedilator 1102. A connector (not shown) can be inserted into the plug 1108to connect the dilator 1102 to a monitoring device that can monitor theimpedance in an electrical circuit that includes the contact 1104.Changes in the impedance of the electrical circuit that occur as thecontact 1104 enters a patient's dura can provide an indication ofintrathecal penetration. The dilator 1102 can be configured in a varietyof suitable manners, including in manners at least generally similar tothose described in U.S. patent application Ser. No. 12/895,438, entitledSYSTEMS AND METHODS FOR DETECTING INTRATHECAL PENETRATION, filed Sep.30, 2011, the entirety of which is incorporated herein by reference.Although the illustrated embodiment of FIG. 11 includes a metallic band1105, the mapping contact 1104 can include a variety of suitableconductive materials, e.g., conductive polymers.

Percutaneous implantation systems in accordance with the presenttechnology can provide several benefits. For example, by reducing thenumber of access points necessary for a percutaneous implantation,embodiments in accordance with the present technology can reduce theamount of anesthetic required, reduce infections, and reduce the needfor antibiotics. Additionally, the percutaneous implantation systemsdescribed herein can reduce the number of steps and the amount of timerequired for insertion procedures. For example, while existingprocedures often require a guidewire to be inserted to provide guidancefor an expansion device, embodiments of the present technology caneliminate this step. The embodiment described above with respect toFIGS. 2-6B, for example, provides for the insertion of the dilator 502through the lumen 203 of the cannula 502, without requiring a guidewire.Removing the steps required for the insertion and the eventualwithdrawal of a guidewire reduces the time required to perform a givenimplantation. Furthermore, reducing the number of devices inserted intoa patient can reduce the chance of patient injury (e.g., accidentalspinal taps).

Access systems in accordance with the present technology can provide forthe insertion of high frequency modulation systems, including thosedescribed in the following co-owned patent applications: U.S. patentapplication Ser. No. 12/264,836, filed Nov. 4, 2008, and titledMULTI-FREQUENCY NEURAL TREATMENTS AND ASSOCIATED SYSTEMS AND METHODS;U.S. patent application Ser. No. 12/765,747, filed Apr. 22, 2010, andtitled SELECTIVE HIGH-FREQUENCY SPINAL CORD MODULATION FOR INHIBITINGPAIN WITH REDUCED SIDE EFFECTS AND ASSOCIATED SYSTEMS AND METHODS; andU.S. patent application Ser. No. 13/607,617, filed Sep. 7, 2012, andtitled SELECTIVE HIGH FREQUENCY SPINAL CORD MODULATION FOR INHIBITINGPAIN, INCLUDING CEPHALIC AND/OR TOTAL BODY PAIN WITH REDUCED SIDEEFFECTS, AND ASSOCIATED SYSTEMS AND METHODS. The above referenced patentapplications are incorporated herein by reference in their entireties.

Additional Embodiments

In one embodiment, there is provided a system for implanting a pluralityof medical devices in a patient through a single percutaneous entrypoint, the system comprising: (a) a cannula having a cannula lumenextending therethrough, the cannula lumen having an inside diameter; (b)a first dilator having an outside diameter smaller than the insidediameter of the cannula lumen, the first dilator positionable within thecannula lumen to prevent coring upon insertion of the cannula and thefirst dilator into the patient to produce the percutaneous entry point;and (c) at least one additional dilator, including a final dilator,wherein each additional dilator includes a dilator lumen having aninside diameter larger than an outside diameter of a preceding dilator,and wherein each additional dilator is positionable over a precedingdilator to expand the percutaneous entry point. The system may furthercomprise two leads, each lead having a diameter, and wherein the finaldilator includes a lumen having an inside diameter greater than the sumof the diameters of the leads. The final dilator may include a lumenhaving an elliptical cross-sectional shape, wherein a diameter along afirst axis of the dilator lumen is greater than the sum of the diametersof the leads.

A distal end of the cannula can include a beveled tip having a shovelshape and a distal end of the first dilator can include a beveled tiphaving a shovel shape positioned to align with the beveled tip of thecannula.

The first dilator can include a beveled tip and a removable hub, whereinthe cannula includes a beveled tip, and wherein the removable hub ispositioned to align the beveled tip of the cannula with the beveled tipof the dilator.

The first dilator can include a mapping contact positioned to detectintrathecal penetration.

In another embodiment, a patient system comprises: (a) two leadspositionable to deliver electrical therapy signals, each lead having adiameter; (b) an insertion needle including a cannula and a stylet,wherein the cannula includes a cannula lumen having an inside diameter,and the stylet includes an outside diameter smaller than the insidediameter of the cannula lumen; (c) a first dilator having an outsidediameter smaller than the inside diameter of the cannula lumen andpositionable within the cannula lumen; and (d) at least one additionaldilator, including a final dilator, wherein each additional dilatorincludes a dilator lumen having an inside diameter larger than anoutside diameter of a preceding dilator, wherein each additional dilatoris positionable over a preceding dilator to expand a percutaneous entrypoint, and wherein the final dilator includes a dilator lumen having aninside diameter or width greater than the sum of the diameters of theleads. The final dilator can include an elliptical cross-sectionalshape, wherein the width is a first width along a first cross-sectionalaxis, and wherein the lumen of the final dilator includes a second widthalong a second cross-sectional axis that is smaller than the first widthand larger than the diameter of either of the two leads. The distal endof the cannula and the distal end of the first dilator can form abeveled tip having a shovel shape.

In yet another embodiment, there is provided a method for treating apatient, comprising: (a) inserting or instructing insertion of apreceding dilator into a patient; (b) positioning or instructingpositioning of and advancement of a subsequent dilator over thepreceding dilator and into the patient; (c) removing or instructingremoval of the preceding dilator from the patient; (d) inserting orinstructing insertion of at least two medical devices side by side intothe subsequent dilator; and (e) advancing or instructing advancement ofthe medical devices into the patient. The method may further comprise:(f) inserting or instructing the insertion of a cannula into the patientto create a single percutaneous entry point, wherein the cannula isinserted into the patient simultaneously with the preceding dilator;and/or (g) instructing the monitoring of an electrical circuit thatincludes a mapping contact on the preceding dilator to detectintrathecal penetration. The two medical devices can be two percutaneousleads for the delivery of electrical therapy to the patient.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thevarious embodiments of the technology. For example, some of theembodiments described above include a stylet having a hub. In otherembodiments, a stylet having no hub (and/or a removable hub) can beemployed. Additionally, in some embodiments, a needle having a removablehub can be inserted into a patient to create a percutaneous entry point,and after the hub is removed, a dilator can be slid over the needle toexpand the entry point. Furthermore, although the illustratedembodiments include dilators having round and elliptical shapes,dilators having a variety of other suitable shapes and sizes can beconstructed in accordance with the present technology. For example, insome embodiments dilators can include oval shaped lumens. Furthermore,dilators in accordance with the present technology can have asymmetricaldistal ends (e.g., scarfed or beveled ends) that can incrementally entera percutaneous entry point as the dilator is inserted. That is, aportion of the distal end of the dilator can enter the percutaneousentry point before the remainder of the distal portion. Additionally,although the embodiments described above include several differentcombinations of various features or methods, embodiments in accordancewith the present technology can include additional combinations of anyof the features or methods. Accordingly, the disclosure and associatedtechnology can encompass other embodiments not expressly shown ordescribed herein.

What is claimed is:
 1. A system for implanting multiple medical devicesthrough a single percutaneous entry point, the system comprising: afirst dilator having an outside diameter; and at least one additionaldilator, including a final dilator, wherein each additional dilatorincludes a dilator lumen having an inside diameter larger than anoutside diameter of a preceding dilator, wherein each additional dilatoris positionable over a preceding dilator to expand a percutaneous entrypoint, and wherein the final dilator includes a lumen having an ovalcross-sectional shape to receive at least two medical devices side byside.
 2. The system of claim 1, further comprising two leads, each leadhaving a diameter, and wherein the oval cross-sectional shape includes alength that is greater than the sum of the diameters of the leads. 3.The system of claim 1, further comprising a cannula having a cannulalumen extending therethrough, wherein the outside diameter of the firstdilator is smaller than an inside diameter of the cannula lumen.
 4. Thesystem of claim 3, wherein the first dilator includes a beveled tip anda removable hub, wherein the cannula includes a bevel tip, and whereinthe removable hub is positioned to align the beveled tip of the cannulawith the beveled tip of the dilator.
 5. The system of claim 3, wherein adistal end of the cannula includes a beveled tip having a shovel shape.6. The system of claim 5, wherein a distal end of the first dilatorincludes a beveled tip having a shovel shape positioned to align withthe beveled tip of the cannula.
 7. The system of claim 3, wherein thefirst dilator includes a mapping contact positioned to detectintrathecal penetration.
 8. The system of claim 7, wherein the mappingcontact includes a metallic band that extends around the circumferenceof the dilator at a distal end of the dilator.